JP7227709B2 - Solid-state imaging device and imaging device - Google Patents

Description

The present technology relates to a solid-state imaging device and an imaging device. Specifically, the present invention relates to a solid-state imaging device having vertical signal lines wired therein, and an imaging apparatus.

2. Description of the Related Art Conventionally, solid-state imaging devices have been used to capture image data in imaging devices and the like. Generally, in a solid-state imaging device, a plurality of pixel circuits are arranged in a two-dimensional grid pattern, and vertical signal lines are wired for each column. The pixel circuits then output signals via those vertical signal lines. Here, if a parasitic capacitance occurs in the vertical signal line, the settling time required for the potential of the vertical signal line to become constant is lengthened due to the parasitic capacitance. Therefore, in order to reduce the influence of the parasitic capacitance, a solid-state imaging device has been proposed in which a current mirror circuit that supplies a current proportional to the degree of potential drop of the vertical signal line is connected to the vertical signal line (see, for example, Patent Document 1).

JP 2011-234243 A

In the conventional technology described above, by supplying a current proportional to the degree of decrease in the potential of the vertical signal line, it is possible to shorten the settling time until the potential becomes constant, thereby improving the readout speed. However, the connection of the current mirror circuit may increase noise and degrade signal quality. If the wiring capacitance of the vertical signal line, including the parasitic capacitance, is reduced, it is possible to eliminate the need for a current mirror circuit and suppress deterioration in signal quality. need to be improved.

The present technology was created in view of such circumstances, and aims to facilitate reduction of the wiring capacitance of vertical signal lines in a solid-state imaging device that outputs signals via vertical signal lines. .

The present technology has been made to solve the above-described problems, and a first aspect of the present technology includes a logic circuit that processes an analog signal, and a logic circuit that generates the analog signal by photoelectric conversion and transmits it to a predetermined signal line. and a negative capacitance circuit connected to the predetermined signal line. This brings about the effect of reducing the wiring capacitance of the predetermined signal line.

In the first aspect, the negative capacitance circuit includes an amplifier having an input terminal connected to the predetermined signal line, and a capacitor having both ends connected to the input terminal and the output terminal of the amplifier. may This brings about the effect of reducing the wiring capacitance of the signal line according to the gain greater than "1".

The first aspect further comprises a current source connected to the predetermined signal line, wherein the negative capacitance circuit is an insertion transistor inserted between the current source and the predetermined signal line. an amplifier comprising a pair of cascode-connected transistors between a power source and a reference terminal; one end connected to a connection point between the pair of transistors; and the other end connected to a connection point between the current source and the insertion transistor The gate of the transistor of the pair of transistors connected to the power supply may be connected to the predetermined signal line. As a result, the wiring capacitance of the signal line is reduced by the gain of "1" or less.

Further, in this first aspect, a first bias voltage is applied to the gate of the insertion transistor, and the current source is a second bias voltage to which a second bias voltage different from the first bias voltage is applied. A transistor may be provided. This brings about an effect that the wiring capacitance is reduced by the negative capacitance circuit in which different bias voltages are applied to the first and second transistors.

Also in this first aspect, a first bias voltage is applied to the gate of the insertion transistor, the current source comprises a second transistor, the gate of the insertion transistor being the gate of the second transistor. may be connected to As a result, the wiring capacitance is reduced by the negative capacitance circuit in which the same bias voltage is applied to the first and second transistors.

The first aspect further comprises a current source connected to the predetermined signal line, wherein the negative capacitance circuit is an insertion transistor inserted between the current source and the predetermined signal line. an amplifier having an input terminal connected to the predetermined signal line; and a capacitor having one end connected to the input terminal of the amplifier and the other end connected to a connection point between the current source and the insertion transistor. You may prepare. As a result, the wiring capacitance of the signal line is reduced by the negative capacitance circuit with the increased negative capacitance value.

The first aspect further comprises a current source connected to the predetermined signal line, and the logic circuit is a comparator that compares the analog signal and a predetermined reference signal and outputs a comparison result. and a control circuit that generates a control signal based on the comparison result and outputs the control signal to the negative capacitance circuit. This brings about the effect that the control signal is generated from the analog signal.

In the first aspect, the negative capacitance circuit includes an insertion transistor and a capacitor inserted between the current source and the predetermined signal line, and an input terminal connected to the predetermined signal line. a first switch for opening and closing a path between one end of the capacitor and the output terminal of the amplifier; and a second switch connecting the other end of the capacitor. As a result, the wiring capacitance of the signal line is reduced by the negative capacitance circuit sharing the capacitor with the successive approximation circuit.

Further, in the first aspect, the comparator includes a dividing circuit that divides the voltage between the analog signal and the predetermined reference signal and outputs the voltage as an input voltage, and a difference between the input voltage and the predetermined voltage. and a differential amplifier circuit that amplifies the . This has the effect of lowering the operating voltage of the comparator.

In the first aspect, the negative capacitance circuit includes an insertion transistor and a capacitor inserted between the current source and the predetermined signal line, and an input terminal connected to the predetermined signal line. a first switch for opening and closing a path between an amplifier, a connection point of the insertion transistor and the current source, and one end of the capacitor; and a second switch connecting the other end of the capacitor. As a result, the wiring capacitance of the signal line is reduced by the negative capacitance circuit sharing the capacitor with the successive approximation circuit.

The first aspect further comprises a current source connected to the predetermined signal line, wherein the negative capacitance circuit is an insertion transistor inserted between the current source and the predetermined signal line. and an amplifier having an input terminal connected to the predetermined signal line, and a switched capacitor circuit, wherein the switched capacitor circuit opens and closes a path between the capacitor, the output terminal of the amplifier, and one end of the capacitor. a second input switch for opening and closing a path between the connection point of the insertion transistor and the current source and the other end of the capacitor; and the one end and the logic circuit. It is also possible to provide a first output side switch for opening and closing a path between the terminals and a second output side switch for opening and closing a path between the other end and a predetermined reference terminal. As a result, the wiring capacitance of the signal line is reduced by the negative capacitance circuit sharing the capacitor with the sample-and-hold circuit.

Further, in this first aspect, the pixel circuit is arranged on a first semiconductor chip, and the negative capacitance circuit and the logic circuit are arranged on a second semiconductor chip stacked on the first semiconductor chip. may be placed. This brings about the effect of reducing the wiring capacitance of the signal line in the stacked solid-state imaging device.

The first aspect further comprises a first current source connected to the predetermined signal line, wherein the negative capacitance circuit is inserted between the first current source and the predetermined signal line. a second current source; an N-type transistor inserted between the second current source and a power supply and having a gate connected to the predetermined signal line; the power supply and the second current source; a clamp transistor connected in parallel with the N-type transistor between and a connection point between the insertion transistor and the first current source and a connection point between the N-type transistor and the second current source at both ends thereof; and a capacitor. This has the effect of clamping the drain voltage of the second current source.

Moreover, this first aspect may further include a gate voltage supply section for changing the gate voltage of the clamp transistor. This brings about the effect of adjusting the streaking amount.

A second aspect of the present technology includes a logic circuit that processes an analog signal and outputs a digital signal, and a pixel that generates the analog signal by photoelectric conversion and outputs the analog signal to the logic circuit through a predetermined signal line. The imaging apparatus includes a circuit, a negative capacitance circuit connected to the predetermined signal line, and a recording section for recording the digital signal. This brings about the effect of recording the analog signal output from the signal line with the reduced wiring capacity.

According to the present technology, in a solid-state imaging device that outputs a signal via a vertical signal line, it is possible to easily reduce the wiring capacitance of the vertical signal line. Note that the effects described here are not necessarily limited, and may be any of the effects described in the present disclosure.

It is a block diagram showing an example of 1 composition of an imaging device in a 1st embodiment of this art. It is a block diagram showing an example of 1 composition of a solid-state image sensing device in a 1st embodiment of this art. 1 is a circuit diagram showing a configuration example of a pixel circuit according to a first embodiment of the present technology; FIG. It is a block diagram showing an example of composition of a column signal processing part in a 1st embodiment of this art. 1 is a block diagram showing a configuration example of an ADC (Analog to Digital Converter) according to a first embodiment of the present technology; FIG. 1 is a circuit diagram showing a configuration example of a negative capacitance circuit according to a first embodiment of the present technology; FIG. It is a circuit diagram showing a configuration example of a negative capacitance circuit according to a second embodiment of the present technology. It is a circuit diagram showing an example of a linear model in a 2nd embodiment of this art. It is a graph which shows an example of the impedance characteristic of the negative capacity circuit in a 2nd embodiment of this art. It is a circuit diagram which shows one structural example of the negative capacitance circuit in 3rd Embodiment of this technique. It is a circuit diagram showing an example of a linear model in a 3rd embodiment of this art. It is a graph which shows an example of the gain characteristic of the negative capacity circuit in a 3rd embodiment of this art. It is a graph which shows an example of the impedance characteristic of the negative capacity circuit in a 3rd embodiment of this art. It is a circuit diagram showing a configuration example of a negative capacitance circuit according to a fourth embodiment of the present technology. It is a block diagram showing an example of composition of a column signal processing part in a 5th embodiment of this art. It is a circuit diagram which shows one structural example of ADC in 5th Embodiment of this technique. It is a figure showing an example of a state of a column signal processing part other than an AD conversion period in a 5th embodiment of this art. It is a figure which shows an example of the state of the column signal processing part in the AD conversion period in 5th Embodiment of this technique. It is a block diagram which shows one structural example of the column signal processing part in the modification of 5th Embodiment of this technique. It is a circuit diagram which shows one structural example of ADC in the modification of 5th Embodiment of this technique. It is a block diagram which shows one structural example of the column signal processing part in 6th Embodiment of this technique. It is a circuit diagram showing an example of composition of a sample hold circuit in a 6th embodiment of this art. It is a figure which shows an example of the state of the column signal processing part in the odd-numbered sampling period in 6th Embodiment of this technique. It is a figure which shows an example of the state of the column signal processing part in the even-numbered sampling period in 6th Embodiment of this technique. It is a block diagram which shows one structural example of the solid-state image sensor in 7th Embodiment of this technique. It is a block diagram which shows one structural example of the logic chip in 7th Embodiment of this technique. It is a circuit diagram which shows one structural example of the negative capacitance circuit in 8th Embodiment of this technique. It is a graph which shows an example of voltage fluctuation of a vertical signal line and drain voltage in an 8th embodiment of this art. It is a graph which shows an example of a change of ground current and streaking amount in an 8th embodiment of this art. It is a circuit diagram showing an example of composition of a column signal processing part in a 9th embodiment of this art. It is a circuit diagram which shows one structural example of the gate voltage supply part in 9th Embodiment of this technique. FIG. 21 is a graph showing an example of variations in ground current and streaking amount in the ninth embodiment of the present technology; FIG. It is a circuit diagram which shows one structural example of the comparator in 10th Embodiment of this technique. 1 is a block diagram showing a schematic configuration example of a vehicle control system; FIG. FIG. 4 is an explanatory diagram showing an example of an installation position of an imaging unit;

Hereinafter, a form for carrying out the present technology (hereinafter referred to as an embodiment) will be described. Explanation will be given in the following order.
1. First Embodiment (Example of Connecting a Negative Capacitance Circuit to a Vertical Signal Line)
2. Second Embodiment (Example of Connecting a Negative Capacitance Circuit Provided with an Amplifier with a Small Gain to Vertical Signal Lines)
3. Third Embodiment (Example in which a negative capacitance circuit in which one of two divided transistors is arranged is connected to a vertical signal line)
4. Fourth Embodiment (Example of Connecting a Negative Capacitance Circuit in Which One of the Transistors Divided into Two and an Amplifier with a Large Gain Are Connected to Vertical Signal Lines)
5. Fifth Embodiment (Example of Connecting a Negative Capacitance Circuit Sharing a Capacitor with an ADC to Vertical Signal Lines)
6. Sixth Embodiment (Example of Connecting a Negative Capacitance Circuit Sharing a Capacitor with a Sample-and-Hold Circuit to Vertical Signal Lines)
7. Seventh Embodiment (Example of Connecting a Negative Capacitance Circuit to a Vertical Signal Line in a Stacked Solid-State Imaging Device)
8. Eighth Embodiment (Example of Connecting a Negative Capacitance Circuit Adding a Clamp Transistor to a Vertical Signal Line)
9. Ninth Embodiment (Example of Connecting a Negative Capacitance Circuit Adding a Clamp Transistor to a Vertical Signal Line and Controlling the Gate Voltage of the Clamp Transistor)
10. Tenth Embodiment (Example of Connecting a Negative Capacitance Circuit to a Vertical Signal Line and Using a Low-Voltage Comparator)
11. Example of application to mobile objects

<1. First Embodiment>
[Configuration example of imaging device]
FIG. 1 is a block diagram showing a configuration example of an imaging device 100 according to the first embodiment of the present technology. This imaging device 100 is a device for capturing image data, and includes an imaging lens 110 , a solid-state imaging device 200 , a recording section 120 and an imaging control section 130 . As the imaging device 100, for example, in addition to a digital camera such as a digital still camera, a smart phone, a personal computer, an in-vehicle camera, and the like having an imaging function are assumed.

The imaging lens 110 collects incident light and guides it to the solid-state imaging device 200 . The solid-state imaging device 200 captures image data under the control of the imaging control section 130 . The solid-state imaging device 200 supplies captured image data to the recording unit 120 via the signal line 209 .

The imaging control section 130 controls the solid-state imaging device 200 . For example, the imaging control unit 130 generates a vertical synchronization signal of a constant frequency (eg, 30 Hz) indicating imaging timing, and supplies it to the solid-state imaging device 200 via the signal line 139 . The recording unit 120 records image data.

[Configuration example of solid-state imaging device]
FIG. 2 is a block diagram showing a configuration example of the solid-state imaging device 200 according to the first embodiment of the present technology. This solid-state imaging device 200 includes a vertical driver 210 , a pixel array section 220 , a timing control section 240 and a DAC (Digital to Analog Converter) 250 . The solid-state imaging device 200 also includes a column signal processing section 300 , a horizontal transfer scanning circuit 260 and an image signal processing section 270 . These circuits are assumed to be mounted on a single semiconductor chip.

A plurality of pixel circuits 230 are arranged in a two-dimensional lattice in the pixel array section 220 . Hereinafter, a set of pixel circuits 230 arranged in a predetermined direction (horizontal direction, etc.) in the pixel array section 220 will be referred to as a "row", and a set of pixel circuits 230 arranged in a direction perpendicular to the row will be referred to as a "column". called. The pixel array section 220 has M rows (M is an integer) and N columns (N is an integer). Further, in the pixel array section 220, 229-n (n is an integer from 1 to N) are wired along the column direction for each column.

The vertical driver 210 sequentially selects and drives rows. A control method for sequentially driving rows in this way is called a rolling shutter method. Note that the vertical driver 210 may use a global shutter method that drives all rows simultaneously instead of the rolling shutter method.

The timing control section 240 controls the operation timings of the vertical driver 210, DAC 250, column signal processing section 300 and horizontal transfer scanning circuit 260 in synchronization with the vertical synchronization signal VSYNC.

The DAC 250 generates a predetermined reference signal through DA (Digital to Analog) conversion and supplies it to the column signal processing section 300 . A sawtooth ramp signal, for example, is used as the reference signal.

The pixel circuit 230 generates an analog pixel signal by photoelectric conversion. The n-column pixel circuits 230 output pixel signals to the column signal processing unit 300 via vertical signal lines 229-n.

The column signal processing unit 300 performs signal processing such as AD (Analog to Digital) conversion processing on pixel signals for each column. The column signal processing section 300 sequentially supplies the data after signal processing to the image signal processing section 270 as pixel data under the control of the horizontal transfer scanning circuit 260 . One sheet of image data is generated from M×N pieces of pixel data.

The horizontal transfer scanning circuit 260 controls the column signal processing section 300 to sequentially output pixel data.

The image signal processing unit 270 executes predetermined image processing such as white balance processing and pixel addition processing on image data. The image signal processing section 270 outputs the processed image data to the recording section 120 .

Although the image signal processing unit 270 is arranged inside the solid-state imaging device 200 , part or all of the image signal processing unit 270 may be arranged outside the solid-state imaging device 200 .

[Configuration example of pixel circuit]
FIG. 3 is a circuit diagram showing a configuration example of the pixel circuit 230 according to the first embodiment of the present technology. This pixel circuit 230 includes a photodiode 231 , a transfer transistor 232 , a reset transistor 233 , a floating diffusion layer 234 , an amplification transistor 235 and a selection transistor 236 .

The photodiode 231 photoelectrically converts incident light to generate charges. The transfer transistor 232 transfers charges from the photodiode 231 to the floating diffusion layer 234 according to the transfer signal TX from the vertical driver 210 .

The reset transistor 233 extracts charges from the floating diffusion layer 234 according to the reset signal RST from the vertical driver 210 to initialize the amount of charge.

The floating diffusion layer 234 accumulates charges transferred from the photodiode 231 and generates a voltage corresponding to the accumulated charge amount.

The amplification transistor 235 amplifies the voltage signal of the floating diffusion layer 234 . The selection transistor 236 outputs the signal amplified by the amplification transistor 235 according to the selection signal SEL from the vertical driver 210 as a pixel signal to the column signal processing section 300 via the vertical signal line 229-n.

Note that the configuration of the pixel circuit 230 is not limited to that illustrated in FIG. 3 as long as it can generate a pixel signal by photoelectric conversion. For example, a shared structure in which a plurality of pixels share the floating diffusion layer 234 may be employed.

[Configuration example of column signal processing unit]
FIG. 4 is a block diagram showing one configuration example of the column signal processing unit 300 according to the first embodiment of the present technology. This column signal processing section 300 includes a negative capacitance circuit 310, a current source 320, an ADC 331, a switch 334 and a memory 335 for each column. Since the number of columns is N, each of N negative capacitance circuits 310, current sources 320, ADCs 331, switches 334 and memories 335 is arranged.

Current source 320 provides a constant current. This current source 320 is inserted between the vertical signal line 229-n of the corresponding column and the terminal of the reference potential (ground potential, etc.).

The negative capacitance circuit 310 is a circuit that functions as a negative capacitance capacitor. In general, when a parasitic capacitance occurs in a vertical signal line and the wiring capacitance increases, the settling time until the potential of the vertical signal line becomes constant is lengthened due to the increase in the wiring capacitance. This may reduce the read speed. However, since the negative capacitance circuit 310 is connected to the vertical signal line 229-1, it is possible to reduce the wiring capacitance and suppress the decrease in read speed.

Wiring capacitance can be reduced by changing the material of the vertical signal line to one with a lower dielectric constant or by miniaturizing the process rule, but process development requires a great deal of time and money, and is accompanied by difficulties. On the other hand, the method of connecting the negative capacitance circuit 310 does not require changing the material of the vertical signal line, so that the wiring capacitance can be easily reduced.

The ADC 331 performs AD conversion on the analog signal (pixel signal) Ain output via the vertical signal line 229-n of the corresponding column. This ADC 331 compares the reference signal REF from the DAC 250 with the analog signal Ain and generates a digital signal Dout based on the comparison result. ADC 331 outputs the digital signal Dout to switch 334 . Note that the ADC 331 is an example of the logic circuit described in the claims.

The switch 334 outputs the digital signal Dout from the ADC 331 of the corresponding column to the memory 335 as pixel data under the control of the timing control section 240 .

The memory 335 holds the pixel data of the corresponding column. This memory 335 outputs pixel data to the image signal processing section 270 under the control of the horizontal transfer scanning circuit 260 .

[Example of configuration of ADC]
FIG. 5 is a block diagram showing a configuration example of the ADC 331 according to the first embodiment of the present technology. This ADC 331 comprises a comparator 332 and a counter 333 .

The comparator 332 compares the analog signal Ain from the pixel circuit 230 in the pixel array section 220 with the reference signal REF from the DAC 250 . The comparator 332 outputs a comparison result signal indicating the comparison result to the counter 333 . As the comparator 332, for example, a differential amplifier circuit that amplifies the difference between the analog signal Ain and the reference signal REF is used.

The counter 333 counts the count value in synchronization with the clock signal CLK from the timing control section 240 over a period in which the comparison result signal is at a predetermined level. The counter 333 outputs a digital signal Dout indicating the count value to the switch 334 .

Note that the ADC 331 may further perform CDS (Correlated Double Sampling) processing for obtaining the difference between the reset level and the signal level. Here, the reset level is the level of the analog signal Ain immediately after resetting, and the signal level is the level of the analog signal Ain immediately after charge transfer to the floating diffusion layer 234 . When performing CDS processing, for example, the counter 333 executes a down counter during AD conversion of the reset level and executes an up counter during AD conversion of the signal level. This provides net pixel data of the difference between the reset level and the signal level.

Further, AD conversion is performed by a ramp type ADC 331 including a comparator 332 and a counter 333, but the ADC is not limited to a ramp type such as a successive approximation type described later.

[Configuration example of negative capacitance circuit]
FIG. 6 is a circuit diagram showing a configuration example of the negative capacitance circuit 310 according to the first embodiment of the present technology. Negative capacitance circuit 310 includes amplifier 311 and capacitor 312 . An input terminal of the amplifier 311 is connected to the vertical signal line 229-n. It is assumed that the gain of this amplifier 311 is larger than "1". Both ends of the capacitor 312 are connected to the input terminal and the output terminal of the amplifier 311 .

Also, the current source 320 is implemented by an N-type transistor 321 . A predetermined bias voltage Vb 1 is applied to the gate of this N-type transistor 321 . The source of the N-type transistor 321 is connected to the vertical signal line 229-n, and the drain is connected to a terminal of a predetermined reference potential (eg, ground potential). As the N-type transistor 321, for example, a MOS (Metal-Oxide-Semiconductor) transistor is used.

It is also assumed that a parasitic capacitance 500 is generated in the vertical signal line 229-n. Assuming that the potential of the vertical signal line 229-n is Vs and the potential on the opposite side of the vertical signal line 229-n (ground potential) is used as a reference, a voltage of +Vs is applied to the parasitic capacitance 500. FIG.

On the other hand, in the negative capacitance circuit 310, if the gain of the amplifier 311 is set to "2", Vs is applied to the terminal on the vertical signal line 229-n side of the capacitor 312, and 2Vs is applied to the terminal on the opposite side. be. Therefore, a voltage of -Vs is applied to the capacitor 312 when the potential (2Vs) on the side opposite to the vertical signal line 229-n is used as a reference.

Since +Vs is applied to the parasitic capacitance 500 and -Vs is applied to the capacitor 312, the wiring capacitance of the vertical signal line 229-n is reduced compared to the case where the negative capacitance circuit 310 is not connected. Assuming that the capacitances of parasitic capacitance 500 and capacitor 312 are the same, the sum of the respective charges of parasitic capacitance 500 and capacitor 312 is "0" coulombs (C). Therefore, the total capacitance of parasitic capacitance and negative capacitance (that is, wiring capacitance) is "0" Farad (F).

Note that the gain of the amplifier 311 is not limited to “2”, and may be a value other than “2” as long as the value can sufficiently reduce the influence of the parasitic capacitance 500 . However, if the gain is "1" or less, the capacitance of the negative capacitance circuit 310 does not become negative, so the gain is set to a value greater than "1".

As described above, in the first embodiment of the present technology, since the negative capacitance circuit 310 is connected to the vertical signal line 229-n, compared with the case where the negative capacitance circuit 310 is not connected, the vertical signal line 229-n n wiring capacity can be reduced. As a result, the settling time until the potential of the vertical signal line 229-n becomes constant can be shortened, and the reading speed can be increased. In addition, since it is not necessary to change the material of the vertical signal line 229-1 or refine the process rule, the wiring capacity can be easily reduced.

<2. Second Embodiment>
In the first embodiment described above, the amplifier 311 having a gain greater than "1" is arranged in the negative capacitance circuit 310. Variation in gain increases. If there is a large variation in gain between columns, the signal level will vary between columns even if the brightness is the same, and the image quality of the image data will be degraded. The negative capacitance circuit 310 of the second embodiment is different from that of the first embodiment in that the negative capacitance circuit 310 is improved to suppress deterioration in image quality of image data.

FIG. 7 is a circuit diagram showing a configuration example of the negative capacitance circuit 310 according to the second embodiment of the present technology. The negative capacitance circuit 310 of the second embodiment differs from the first embodiment in that it further includes an N-type transistor 313 and includes an amplifier 314 instead of the amplifier 311 .

Amplifier 314 comprises N-type transistors 315 and 316 cascode-connected between a power supply and a terminal of a reference potential (such as ground potential). The gate of the N-type transistor 315 is connected to the vertical signal line 229-n, and the gate of the N-type transistor 316 is applied with a bias voltage Vb1'. The value of this bias voltage Vb1' may be the same value as the bias voltage Vb1, or may be a different value. If they are the same, the scale of the circuit that supplies the bias voltage can be reduced.

Also, the N-type transistor 313 is cascode-connected to the N-type transistor 321 serving as a current source. In other words, the N-type transistor 313 is inserted between the vertical signal line 229-n and the current source. A bias voltage Vb2 different from the bias voltage Vb1 is applied to the gate of this N-type transistor 313 . As N-type transistors 313, 315 and 316, for example, MOS transistors are used. Note that the N-type transistor 313 is an example of an insertion transistor described in the claims.

One end of capacitor 312 is connected to the connection point of N-type transistors 313 and 321 , and the other end of capacitor 312 is connected to the connection point of N-type transistors 315 and 316 .

FIG. 8 is a circuit diagram showing a configuration example of a linear model according to the second embodiment of the present technology; The circuit in FIG. 7 can be represented by the linear model of FIG. In this linear model, the transconductance of node N1 on vertical signal line 229-n and the path between nodes N1 and N2 is g _m1 . Also, the mutual conductance of the path between node N1 and node N3 is _gm2 . The transconductance of the loop circuit connected to node N3 is g _m2 . Also, R is the resistance of the path between the node N2 and the ground potential. A capacitor of capacitance C is inserted between node N3 and node N2. The potential of the node N1 is _v1 , the potential of the node N2 is _v2 , and the potential of the node N3 is _v3 .

The following charge conservation equation holds for each node.
g _m1 v ₁ = v ₂ /R+sC(v ₂ −v ₃ ) Equation 1
sC(v ₂ −v ₃ )=g _m2 v ₃ Equation 2
i ₁ =-g _m2 v ₃ Equation 3
In the above formula, s represents a complex number. _i1 represents the current flowing through the vertical signal line 229-n. The unit of _i1 is, for example, ampere (A), and the unit of transconductances _gm1 and _gm2 is, for example, siemens (G). The unit of resistance R is, for example, ohms, and the unit of potentials v1, v2 and v3 is, for example, volts (v).

Equation 2 can be transformed into the following equation.

From Equation 4, the linear model has the properties of a high-pass filter with a pole at the angular frequency g _m2 /C. Next, the following equation is obtained from equations 1 and 3.

From Equation 5, the linear model has a transfer characteristic that has a zero point at the angular frequency g _m2 /C and a pole at a lower angular frequency g _m2 /{C(1+g _m2 R)}. Substituting equations 4 and 5 into equation 3 yields the following equation.

上式において、インピーダンスＺの単位は、オームである。 From Equation 6, the impedance Z of the linear model as the load is expressed by the following equation.

In the above equation, the unit of impedance Z is ohms.

A low frequency approximation to Equation 7 yields the following equation.

From Equation 8, the linear model has a negative capacitance of -g _m1 R·C when the angular frequency is well below g _m2 /{C(1+g _m2 R)}. In other words, the negative capacitance value is the product of the capacitance of the capacitor 312 and the DC (Direct Current) gain of the amplifier 314 . Contrary to simple intuition, the transconductance g _m2 does not appear in negative capacitance values. Also, from Equation 7, the impedance Z in the high frequency band is expressed by the following equation.

From Equation 9, the linear model does not become ideal negative capacitance, but becomes negative resistance in the high frequency band. Depending on the parasitic capacitance of the vertical signal line 229-n, the vertical signal line 229-n may become unstable if the negative capacitance is not ideal. For example, it can cause ringing. Therefore, it is preferable to increase the negative capacitance value −g _m1 R·C as much as possible while maintaining the zero point angular frequency g _m2 /{C(1+g _m2 R)} as large as possible. In terms of design parameters, the mutual conductance g _m1 of the amplifier 314 should be large from the viewpoint of increasing the negative capacitance value, and the mutual conductance g _m2 of the N-type transistor 313 should be large from the viewpoint of maintaining stability. is preferred. Also, from the viewpoint of increasing the negative capacitance value, it is preferable that the resistance R and the capacitance C are large, but from the viewpoint of maintaining stability, it is preferable that they are small. Considering the case where a source follower is used for the amplifier 314, the following equation holds because the resistance R is 1/g _m1 .

10, the negative capacitance value is −C and is determined only by the capacitance C of capacitor 312 . On the other hand, the zero point frequency is represented by the following equation.

From Equation 11, both mutual conductances g _m1 and g _m2 are required to be large. On the other hand, the zero point frequency is determined by the smaller of these mutual conductances, and the mutual conductance is almost determined by the bias current, so care must be taken when calculating the current consumption. becomes.

Note that when the source follower is replaced with a super source follower, first, the DC gain g _m1 R does not change and is approximately "1", so the negative capacitance value remains -C, but the mutual conductance g _m1 increases by one stage of the intrinsic gain. Therefore, it can be considered that the stability is improved. A similar effect can be obtained by increasing the bias current of the source follower, but from the viewpoint of increasing the mutual conductance g _m1 , the super source follower configuration is considered to have better current efficiency.

As described above, even if the gain of the amplifier 314 is "1" or less, the capacitance of the negative capacitance circuit 310 is negative. Therefore, the circuit scale of the negative capacitance circuit 310 can be reduced compared to the first embodiment in which the gain of the amplifier must be greater than "1". In addition, it is possible to suppress variations in gain for each column and improve image quality of image data.

FIG. 9 is a graph showing an example of impedance characteristics of the negative capacitance circuit 310 according to the second embodiment of the present technology. The vertical axis in the figure is the impedance Z, and the horizontal axis is the angular frequency. From the figure, the capacitance is −C in the frequency band lower than the zero point frequency.

As described above, according to the second embodiment of the present technology, since the N-type transistor 313 cascode-connected to the current source and the amplifier 314 including a pair of cascode-connected transistors are provided, the gain of the amplifier 314 is can be less than or equal to "1". As a result, it is possible to suppress variations in gain for each column and improve the image quality of the image data.

<3. Third Embodiment>
In the second embodiment described above, the N-type transistor 313 is inserted between the N-type transistor 321 of the current source and the vertical signal line 229-n. The insertion of this N-type transistor 313 may lead to a reduction in dynamic range, an increase in the total area of the transistors, and an increase in the circuit scale of the circuit that supplies the bias voltage. The negative capacitance circuit 310 of the third embodiment differs from that of the second embodiment in that the N-type transistor 313 is eliminated.

FIG. 10 is a circuit diagram showing a configuration example of the negative capacitance circuit 310 according to the third embodiment of the present technology. The negative capacitance circuit 310 of the third embodiment does not include the N-type transistor 313, but includes N-type transistors 321-1 and 321-2 in place of the N-type transistor 321, unlike the second embodiment. different from

The N-type transistors 321-1 and 321-2 are cascode-connected between the vertical signal line 229-n and the ground potential, and a bias voltage Vb1 is applied to their gates. Further, the sum of the gate lengths of N-type transistors 321-1 and 321-2 is equal to the gate length of N-type transistor 321, and the gate width of each of N-type transistors 321-1 and 321-2 is equal to the N-type transistor 321-1 and 321-2. It is equal to the gate width of transistor 321 . That is, the N-type transistors 321-1 and 321-2 are equivalent to dividing the N-type transistor 321 into two.

Also, one end of the capacitor 312 is connected to the connection point of the N-type transistors 321-1 and 321-2. N-type transistor 321-2 on the ground side is used as a current source, and N-type transistor 321-1, capacitor 312 and amplifier 314 are arranged in negative capacitance circuit 310. FIG.

In this way, the current source N-type transistor 321 is divided into two N-type transistors 321-1 and 321-2, and one of them is used instead of the N-type transistor 313. Total area can be reduced. Note that the N-type transistor 321-1 is an example of the insertion transistor described in the claims.

ｉ_１＝－ｇ_ｍ２ｖ_３ ・・・式１４ FIG. 11 is a circuit diagram showing a configuration example of a linear model according to the third embodiment of the present technology; The circuit in FIG. 10 can be represented by the linear model in FIG. The linear model of the third embodiment differs from that of the second embodiment in that the resistance value of the path between the node N3 and the terminal of the reference potential is _R2 . The following charge conservation equation holds for each node.
g _m1 v ₁ = v ₂ /R+sC(v ₂ −v ₃ ) Equation 12

i ₁ =-g _m2 v ₃ Equation 14

Comparing the equations 1 to 3 of the second embodiment with the equations 12 to 14 of the third embodiment, it is characteristic that the effective transconductance g′ _m2 appears in the equation 13. be. Transformation of Equation 13 yields the following equation.

From Equation 15, the linear model is a high-pass filter with a pole at the angular frequency g' _m2 /C. Also, the following equation is obtained from equations 12 and 14.

From Equation 16, the linear model has a transfer characteristic with a zero point at angular frequency g _m2 /C and a pole at lower angular frequency g _m2 /{C(1+g _m2 R)}. Substituting equations 15 and 16 into equation 14 yields:

From Equation 17, the impedance Z of the linear model as the load is expressed by the following equation.

Next, the resistance _R2 and the transconductance _gm2 , which are inherent parameters in the third embodiment, are obtained. First, the mutual conductance g _m2 is saturated, so the following formula holds.
I _d =(k/A)·(V _g −V−V _th ) ² Equation 19
In the above equation, I _d is the drain current of N-type transistor 321-1 or 321-2. A is the gate length ratio of the N-type transistors 321-1 and 321-2, that is, the division ratio. k is a predetermined coefficient. _Vg is the gate voltage. V is the voltage of the split node. V _th is the threshold voltage. The unit of these voltages is, for example, volts (V).

Transformation of Equation 19 yields the following equation.
V=V _g −V _th −(A·I _d /k) ^1/2 Equation 20

Further, by differentiating both sides of Equation 19, the following equation is obtained.
I _d =2(k/A)·(V _g −V−V _th )
=2 {(k·Id)/A} ^1/2
=(1/A ^1/2 )·g _{m_LM0} Expression 21
In the above equation, _{gm_LM0} is the transconductance of N-type transistor 321 before splitting.

Next, regarding the resistor _R2 , the N-type transistor 321-2 corresponding to the resistor _R2 is a three-electrode region, so the following equation holds.
I _d ={2k/(1−A)}·{(V _g −V _th )V−V ² /2} Equation 22

From Equations 20 and 22, the following equation is obtained.
R ₂ = {(1−A)/2k}·{1/( _Vg − _Vth −V)}
= {(1−A)/2}·{1/(A·k·Id)} ^1/2
= {(1−A)/(2A ^1/2 )}・(1/g _{m_LM0} ) Equation 23

Similarly, the following equation is obtained for g' _m2 .
g′ _m2 =g _m2 +1/R ₂
= {1/A ^1/2 +2A ^1/2 /(1−A)}・g _{m_LM0}
= (1/A ^1/2 ) {(1+A)/(1−A)}·g _{m_LM0} Equation 24

Also, from Equation 18, the impedance Z in the low frequency band is expressed by the following equation.

g _m1 ·R in the above equation represents the gain of the amplifier 314 . Assuming that a source follower with a gain of "1" is used as the amplifier 314, Equation 25 is expressed by the following equation.

From Equation 26, the negative capacitance circuit 310 has a negative capacitance of -(g _m /g' _m2 )·C. In the negative capacitance of the third embodiment, unlike the second embodiment, a coefficient of the mutual conductance ratio g _m /g' _m2 appears. This factor is the negative capacitance gain. This negative capacitance gain is represented by the following equation.
g _m /g' _m2 = (1-A)/(1+A) Equation 27

FIG. 12 is a graph showing an example of gain characteristics of the negative capacitance circuit 310 according to the third embodiment of the present technology. The vertical axis in the figure is the negative capacitance gain exemplified in Equation 27, and the horizontal axis is the division ratio A.

Also, from Equation 18, the impedance Z in the high frequency band is expressed by the following equation.

From Equation 28, in the third embodiment, the impedance Z becomes a negative resistance as in the second embodiment. If a source follower with a gain of "1" is used as the amplifier 314, the impedance Z is expressed by the following equation.

Similarly, consider the intermediate frequency band expressed by the following equation.

Impedance Z in the intermediate frequency band shown in Equation 30 is expressed by the following equation.
Z= _v1 / _i1
=-( _gm / _g'm2 )・(1/ _gm1 +1/ _gm2 )
=-{(1+A)/(1-A)}・(1/g _m1 +1/g _m2 )...Equation 31

From Equation 31, the impedance Z becomes a negative resistance in the intermediate frequency band.

FIG. 13 is a graph showing an example of impedance characteristics of the negative capacitance circuit 310 according to the third embodiment of the present technology. The vertical axis in the figure indicates the impedance Z, and the horizontal axis indicates the angular frequency. The graph in the figure is obtained from Equations 26, 29 and 31. As illustrated in the figure, two poles and two zeros appear in the impedance characteristic of the negative capacitance circuit 310 .

As described above, in the third embodiment of the present technology, the N-type transistor 321 is divided into two and one of the two is arranged in the negative capacitance circuit 310, so the N-type transistor 313 can be eliminated.

<4. Fourth Embodiment>
In the third embodiment described above, the amplifier 314 with a gain of "1" is arranged in the negative capacitance circuit 310, but there is a possibility that a sufficiently large negative capacitance value cannot be obtained with this configuration. The negative capacitance circuit 310 of the fourth embodiment differs from that of the third embodiment in that the negative capacitance value is increased.

FIG. 14 is a circuit diagram showing a configuration example of the negative capacitance circuit 310 according to the fourth embodiment of the present technology. The negative capacitance circuit 310 of the fourth embodiment differs from the third embodiment in that an amplifier 311 having a gain greater than "1" is arranged instead of the amplifier 314. FIG. Due to the placement of the amplifier 311, the negative capacitance value increases more than in the case of the third embodiment. However, from the viewpoint of maintaining stability, it is desirable to suppress the output impedance (that is, the resistance R in the linear model).

As described above, in the fourth embodiment of the present technology, the amplifier 311 having a gain larger than "1" is arranged, so that the negative capacitance value can be increased.

<5. Fifth Embodiment>
In the fourth embodiment described above, the capacitor 312 is arranged outside the ADC 331 for each column, but there is a possibility that the circuit scale will increase as the number of columns increases. For example, when the ADC has a built-in capacitor, if the capacitor is shared by the ADC and the negative capacitance circuit 310, the circuit scale can be reduced. The negative capacitance circuit 310 of the fifth embodiment differs from that of the fourth embodiment in that it shares a capacitor with the ADC.

FIG. 15 is a block diagram showing one configuration example of the column signal processing unit 300 according to the fifth embodiment of the present technology. The column signal processing unit 300 of the fifth embodiment has an ADC 370 in place of the ADC 331, does not have the capacitor 312, and further has switches 341 and 343 and a capacitor 342, which are the same as those of the fourth embodiment. different from

A bias voltage Vb1 is applied to one end of the switch 341, and the other end is commonly connected to both gates of the N-type transistors 321-1 and 321-2. This switch 341 opens and closes the path between the source of the bias voltage Vb1 and the gates of both of the N-type transistors 321-1 and 321-2 according to the control signal SW1 from the timing control section 240. FIG.

One end of capacitor 342 is commonly connected to the gates of both N-type transistors 321-1 and 321-2, and the other end is connected to the terminal of reference potential VSS.

The switch 343 opens and closes the path between the output terminal of the amplifier 311 and the ADC 370 according to the control signal SW2 from the timing control section 240 . Note that the switch 343 is an example of the first switch described in the claims.

FIG. 16 is a circuit diagram showing one configuration example of the ADC 370 according to the fifth embodiment of the present technology. This ADC 370 comprises a DAC 371 , a comparator 374 and a successive approximation controller 375 .

The DAC 371 performs DA (Digital to Analog) conversion, and includes a plurality of capacitors 372 having different capacities and switches 373 equal in number to the capacitors 372 .

One end of each of capacitors 372 is commonly connected to the path between switch 343 and the input terminal of comparator 374 . The switch 373 connects the other end of the corresponding capacitor 372 to either the connection point of the N-type transistors 321-1 and 321-2 or the terminal of a predetermined reference potential (ground potential, etc.) based on the digital signal Dout. It connects to Note that the switch 373 is an example of the second switch described in the claims.

The comparator 374 compares the potential of the analog signal Ain from the DAC 371 with a predetermined reference potential (ground potential, etc.). This comparator 374 outputs the comparison result to the successive approximation control section 375 .

The successive approximation controller 375 generates a digital signal Dout from the comparison result of the comparator 374 and feeds it back to the DAC 371 and outputs it to the switch 334 . A circuit including the comparator 374 and the successive approximation controller 375 is an example of the logic circuit described in the claims.

For example, in the initial state, all of the switches 373 connect the connection destination of the corresponding capacitor 372 to the connection point of the N-type transistors 321-1 and 321-2. Then, when the analog signal Ain is higher than the reference potential, the successive approximation control section 375 generates the first bit of the digital signal Dout. According to the first bit, the switch 373 switches the connection destination of the capacitor 372 having the largest capacity to the reference potential to discharge it.

If the analog signal Ain is higher than the reference potential after the generation of the first bit, the successive approximation control unit 375 generates the second bit of the digital signal Dout. According to the second bit, the switch 373 switches the connection destination of the capacitor 372 having the second largest capacity to the reference potential and discharges it. Thereafter, similar control is repeatedly executed. Then, when the analog signal Ain is equal to or lower than the reference potential, the switch 373 does not discharge the capacitor 372, and the comparison operation ends. When the number of bits of the digital signal Dout per pixel is 16 bits, the maximum number of comparisons is 16, and if the comparison operation ends in the middle, the remaining bits are set to fixed values. An ADC that sequentially performs bit-by-bit comparison operations in this manner is called a successive approximation ADC.

FIG. 17 is a diagram illustrating an example of the state of the column signal processing unit 300 during periods other than the AD conversion period according to the fifth embodiment of the present technology. Before AD conversion starts or after AD conversion ends, timing control section 240 closes switches 341 and 343 by means of control signals SW1 and SW2. As a result, the circuit consisting of the N-type transistor 321-1, the amplifier 311, the switch 343 and the capacitor 372 has the same configuration as the negative capacitance circuit 310 of the fourth embodiment.

Also, the capacitor 372 holds the analog signal Ain. Thus, negative capacitance circuit 310 of the fifth embodiment shares capacitor 372 with ADC 370 . Therefore, it becomes unnecessary to dispose the capacitor 312 outside the ADC 370, and the circuit scale of the column signal processing section 300 can be reduced.

Note that the timing control unit 240 stops the supply of the bias voltage Vb1 by opening the switch 341 during the AD conversion period. good. However, it takes longer to charge the capacitor 342, and power consumption may increase.

FIG. 18 is a diagram illustrating an example of the state of the column signal processing section 300 during the AD conversion period according to the fifth embodiment of the present technology. During the AD conversion period, the timing control section 240 opens the switches 341 and 343 by the control signals SW1 and SW2. As a result, the circuit consisting of the N-type transistor 321-1, the amplifier 311, the switch 343 and the capacitor 372 is no longer a loop circuit, and the capacitance is no longer negative. Also, the ADC 370 converts the analog signal Ain held in the capacitor 372 into a digital signal Dout by successive approximation control.

By opening and closing switch 343 as illustrated in FIGS. 17 and 18, negative capacitance circuit 310 can be enabled or disabled. Here, "enable" means that the capacitance of the negative capacitance circuit 310 is negative.

As described above, in the fifth embodiment of the present technology, the capacitor 372 is shared by the negative capacitance circuit 310 and the ADC 370 , so there is no need to arrange the capacitor 312 outside the ADC 370 . As a result, the circuit scale of the column signal processing section 300 can be reduced compared to the case where the capacitor 312 is arranged outside the ADC 370 .

[Modification]
In the fifth embodiment described above, the switch 343 that enables the negative capacitance circuit 310 is connected to the output terminal of the amplifier 311, but if it is on the loop path, the switch 343 can be arranged at another location. be able to. For example, switch 343 can be placed between the connection point of N-type transistors 321-1 and 321-2 and ADC 370. FIG. The column signal processing section 300 in the modified example of the fifth embodiment differs from the fifth embodiment in that the switch 343 is arranged differently.

FIG. 19 is a block diagram showing one configuration example of the column signal processing unit 300 in the modified example of the fifth embodiment of the present technology. The column signal processing unit 300 in the modification of the fifth embodiment is fifth in that the switch 343 is arranged on the path between the connection point of the N-type transistors 321-1 and 321-2 and the ADC 370. Different from the embodiment.

FIG. 20 is a circuit diagram showing one configuration example of the ADC 370 in the modified example of the fifth embodiment of the present technology. One end of each of the capacitors 372 in the ADC 370 of the modification of the fifth embodiment is commonly connected to the path between the switch 373 and the comparator 374 . Also, the switch 373 connects the other end of the capacitor 372 to either the amplifier 311 or the reference potential terminal based on the digital signal Dout.

Thus, according to the modification of the fifth embodiment of the present technology, since the switch 343 is arranged on the path between the connection point of the N-type transistors 321-1 and 321-2 and the ADC 370, the path can be opened and closed. This allows the negative capacitance circuit 310 to be enabled or disabled.

<6. Sixth Embodiment>
In the fifth embodiment described above, the negative capacitance circuit 310 shares the capacitor 372 with the ADC 370, but it can also be shared with circuits other than the ADC. For example, the negative capacitance circuit 310 can share a capacitor with the sample and hold circuit. The negative capacitance circuit 310 of the sixth embodiment differs from that of the fifth embodiment in that it shares a capacitor with the sample-and-hold circuit.

FIG. 21 is a block diagram showing one configuration example of the column signal processing unit 300 according to the sixth embodiment of the present technology. The sixth column signal processing section 300 differs from the fifth embodiment in that the amplifier 311 and the switch 343 are not provided, and the sample hold circuit 350 is further provided. Also, instead of the ADC 370, an ADC 331 that is not a successive approximation type is provided. A successive approximation type ADC 370 can also be arranged as in the fifth embodiment.

The sample and hold circuit 350 takes in (that is, samples) and holds the analog signal from the vertical signal line 229-n. The sample hold circuit 350 supplies the held analog signal Ain to the ADC 331 .

FIG. 22 is a circuit diagram showing one configuration example of the sample and hold circuit 350 according to the sixth embodiment of the present technology. The sample and hold circuit 350 includes an amplifier 351, switches 352-355, capacitors 356 and 357, and switches 358-361.

The input terminal of the amplifier 351 is connected to the pixel circuit 230 via the vertical signal line 229-n, and the output terminal is connected to the switches 352 and 354. FIG. The switch 352 opens and closes the path between one end of the capacitor 356 and the amplifier 351 according to the control signal SMP1 from the timing control section 240 . The switch 353 opens and closes the path between one end of the capacitor 356 and the ADC 331 according to the control signal SMP2 from the timing control section 240 .

The switch 354 opens and closes the path between one end of the capacitor 357 and the amplifier 351 according to the control signal SMP2. The switch 355 opens and closes the path between one end of the capacitor 357 and the ADC 331 according to the control signal SMP1.

The switch 358 opens and closes the path between the other end of the capacitor 356 and the connection point of the N-type transistors 321-1 and 321-2 according to the control signal SMP1. The switch 359 opens and closes the path between the other end of the capacitor 356 and the terminal of the reference potential (ground potential or the like) according to the control signal SMP2.

Switch 360 opens and closes the path between the other end of capacitor 357 and the connection point of N-type transistors 321-1 and 321-2 according to control signal SMP2. The switch 361 opens and closes the path between the other end of the capacitor 357 and the reference potential terminal according to the control signal SMP1.

FIG. 23 is a diagram illustrating an example of the state of the column signal processing unit 300 within the odd-numbered sampling period according to the sixth embodiment of the present technology. During the odd-numbered sampling period, the timing control section 240 closes the switches 352, 355, 358 and 361 with the control signal SMP1 and opens the remaining switches with the control signal SMP2. As a result, the circuit consisting of the N-type transistor 321-1, the amplifier 351, the switch 352, the capacitor 356 and the switch 358 becomes a circuit similar to the negative capacitance circuit 310 of the fourth embodiment, and the capacitance becomes negative. . Capacitor 356 also samples the analog signal, while capacitor 357 holds the even-sampled signal.

FIG. 24 is a diagram illustrating an example of the state of the column signal processing unit 300 within the even-numbered sampling period according to the sixth embodiment of the present technology. During even-numbered sampling periods, the timing control section 240 opens the switches 352, 355, 358 and 361 according to the control signal SMP1, and closes the remaining switches according to the control signal SMP2. As a result, the circuit consisting of the N-type transistor 321-1, the amplifier 351, the switch 354, the capacitor 357 and the switch 360 becomes a circuit similar to the negative capacitance circuit 310 of the fourth embodiment, and the capacitance becomes negative. . Also, capacitor 356 holds the odd-numbered sampled signal, while capacitor 357 samples the analog signal.

As described above, in the circuit consisting of capacitor 356 and switches 352, 353, 358 and 359, switches 352 and 358 on the input side and switches 353 and 359 on the output side alternately open and close. Such a circuit is called a switched capacitor circuit. The circuit consisting of capacitor 357 and switches 354, 355, 360 and 361 similarly functions as a switched capacitor circuit. Although two switched capacitor circuits are arranged, only one may be arranged. However, if only one switched capacitor circuit is used, odd-numbered sampling and even-numbered holding cannot be executed in parallel.

The switches 352 and 354 are examples of the first input-side switches described in the claims, and the switches 358 and 360 are examples of the second input-side switches described in the claims. The switches 353 and 355 are examples of the first output side switches described in the claims, and the switches 359 and 361 are examples of the second output side switches described in the claims.

Thus, in the sixth embodiment of the present technology, the negative capacitance circuit 310 shares a capacitor with the sample-and-hold circuit 350, eliminating the need to dispose the capacitor 312 outside the sample-and-hold circuit 350. FIG. This makes it possible to reduce the circuit scale of the column signal processing section 300 compared to the case where the capacitor 312 is arranged outside the sample hold circuit 350 .

<7. Seventh Embodiment>
In the first embodiment described above, the pixel array section 220 is provided on a single semiconductor chip together with circuits other than the pixel array section 220, such as the timing control section 240. FIG. However, if the area of the semiconductor chip is fixed, the area of the pixel array section 220 may be reduced by the circuits other than the pixel array section 220 . In order to increase the area of the pixel array section 220, for example, each circuit in the solid-state imaging device 200 may be dispersedly arranged in a plurality of stacked semiconductor chips. The solid-state imaging device 200 of the seventh embodiment differs from that of the first embodiment in that circuits are arranged in a distributed manner in a plurality of stacked semiconductor chips.

FIG. 25 is a block diagram showing one configuration example of the solid-state imaging device 200 according to the seventh embodiment of the present technology. A solid-state imaging device 200 of the seventh embodiment comprises a pixel chip 201 and a logic chip 202 which are stacked. A pixel chip 201 is a semiconductor chip on which a pixel array section 220 is arranged. Note that the pixel chip 201 is an example of the first semiconductor chip described in the claims.

FIG. 26 is a block diagram showing one configuration example of the logic chip 202 according to the seventh embodiment of the present technology. This logic chip 202 is a semiconductor chip in which an upper column signal processing section 301, an image signal processing section 270 and a lower column signal processing section 302 are arranged.

In the upper column signal processing unit 301, circuits corresponding to half of all columns of the column signal processing unit 300 are arranged. On the other hand, circuits corresponding to the remaining columns of the column signal processing unit 300 are arranged in the lower column signal processing unit 302 . Vertical driver 210, DAC 250 and horizontal transfer scanning circuit 260 are arranged in logic chip 202, for example. These are omitted in FIG.

As described above, in the seventh embodiment of the present technology, the circuits are distributed and arranged in the stacked pixel chips 201 and the logic chips 202, and thus the pixel array section 220 is compared with the case where the circuits are arranged in a single semiconductor chip. area can be widened.

<8. Eighth Embodiment>
In the second embodiment described above, the negative capacitance circuit 310 is connected to the vertical signal line 229-n to reduce the wiring capacitance, but streaking may occur due to variations in the ground current. The solid-state imaging device 200 of the eighth embodiment differs from the second embodiment in that streaking is suppressed by clamping the drain voltage of the N-type transistor 316 serving as a current source.

FIG. 27 is a circuit diagram showing a configuration example of the negative capacitance circuit 310 according to the eighth embodiment of the present technology. The negative capacitance circuit 310 of each column in the eighth embodiment differs from the second embodiment in that a clamp transistor 383 is further provided. 7, the N-type transistor 321 of FIG. 7 operates as a current source 381, and the N-type transistor 316 operates as a current source 382. FIG. The current supplied by the current source 381 is _I1 , and the current supplied by the current source 382 is _I2 . Also, the gate-source voltage of the N-type transistor 315 is _VGS , and the drain voltage of the current source 382 (N-type transistor 316) is _VD . The current source 381 is an example of the first current source described in the claims, and the current source 382 is an example of the second current source described in the claims.

Clamp transistor 383 is connected in parallel with N-type transistor 315 between the power supply and current source 382 . As the clamp transistor 383, for example, an N-type MOS transistor is used. A fixed gate voltage VGCLP is applied to the gate of this clamp transistor 383 . The same gate voltage VGCLP is supplied to all columns.

FIG. 28 is a graph showing an example of voltage fluctuations of the vertical signal line 229-n and the drain voltage _VD in the eighth embodiment of the present technology. The vertical axis in the figure indicates the voltage of the vertical signal line 229-n or the drain voltage _VD , and the horizontal axis in the figure indicates time. In addition, the thick solid line in the figure indicates the variation in the voltage of the vertical signal line 229-n. A dotted line in FIG. 10 indicates variation of the drain voltage _VD in the second embodiment in which the clamp transistor 383 is not provided. On the other hand, the thin solid line indicates the variation of the drain voltage _VD in the eighth embodiment in which the clamp transistor 383 is provided.

When the transfer signal TX is input to the pixel circuit 230 at timing T0, the voltage of the vertical signal line 229-n drops from DK to OFF after timing T1. DK is a voltage corresponding to dark current, and OF is a voltage corresponding to the amount of incident light.

If the amount of incident light is very large, the amount of DK to OF drop will be large. Even in this case, current source 381 corresponding to current _I1 is designed to operate in the saturation region. On the other hand, the drain voltage _VD of the current source 382 (N-type transistor 316) corresponding to the current _I2 is lower than the voltage of the vertical signal line 229-n by the gate-source voltage _VGS . Therefore, in the second embodiment in which the clamp transistor 383 is not provided, a drop in the drain voltage _VD may cause the current source 382 to operate not in the saturation region but in the linear region. Current _I2 decreases when current source 382 operates in the linear region. Due to the fluctuation of the current _I2 , the total ground current of the currents _I1 and _I2 fluctuates, and the streaking characteristic deteriorates.

Therefore, a clamp transistor 383 is added in the negative capacitance circuit 310 of the eighth embodiment. In this configuration, when the voltage on vertical signal line 229-n drops below gate voltage VGCLP, current _I2 through clamp transistor 382 dominates. The lower the voltage of the vertical signal line 229-n, the higher the ratio of the current flowing through the clamp transistor 382, and the drain voltage _VD is fixed (clamped) at a constant voltage CLP according to the gate voltage VGCLP.

FIG. 29 is a graph showing an example of variations in ground current and streaking amount in the eighth embodiment of the present technology. In the same figure, a is a graph showing an example of variation of the ground current _IGND . b in the figure is a graph showing an example of variation of the difference ΔI _GND between the ground current and the dark current. c in the figure is a graph showing an example of variation in streaking amount. The vertical axis in the figure indicates the current or streaking amount, and the horizontal axis in the figure indicates the voltage VSL of the vertical signal line 229-n. In the same figure, the dotted line indicates variations in ground current and streaking amount in the second embodiment in which the clamp transistor 383 is not provided. On the other hand, the solid line indicates variations in ground current and streaking amount in the eighth embodiment in which the clamp transistor 383 is provided.

In the second embodiment in which the clamp transistor 383 is not provided, as illustrated by the dotted line, fluctuations in the current _I2 cause fluctuations in the total ground current _IGND of the currents _I1 and _I2 , increasing the amount of streaking. . On the other hand, in the eighth embodiment in which the clamp transistor 383 is provided, as illustrated by the solid line, a voltage margin necessary for the operation of the current source 382 in the saturation region can be ensured, thus suppressing fluctuations in the current _I2 . can do. This suppresses fluctuations in the total ground current I _GND of the currents I ₁ and I ₂ and reduces the amount of streaking.

Thus, according to the eighth embodiment of the present technology, the drain voltage _VD of the current source 382 is clamped by the clamp transistor 383, so streaking characteristics can be improved.

<9. Ninth Embodiment>
In the eighth embodiment described above, the gate voltage VGCLP of the clamp transistor 383 is set to a fixed value. The solid-state imaging device 200 of the ninth embodiment differs from the eighth embodiment in that the gate voltage VGCLP is made variable and its value is adjusted.

FIG. 30 is a circuit diagram showing one configuration example of the column signal processing unit 300 according to the ninth embodiment of the present technology. The column signal processing section 300 in the ninth embodiment differs from that in the eighth embodiment in that a gate voltage supply section 410 is further arranged.

The gate voltage supply unit 410 generates a gate voltage VGCLP and supplies it to each of the clamp transistors 383 of all columns.

FIG. 31 is a circuit diagram showing a configuration example of the gate voltage supply section 410 according to the ninth embodiment of the present technology. This gate voltage supply section 410 comprises a variable current source 411 , N-type transistors 412 , 415 and 418 , and switches 413 , 414 , 416 and 417 .

A variable current source 411 and an N-type transistor 412 are connected in series with a power supply. The voltage at the connection point between variable current source 411 and N-type transistor 412 is supplied to the gate of clamp transistor 383 as gate voltage VGCLP.

N-type transistors 415 and 418 are connected in parallel to the connection point of variable current source 411 and N-type transistor 412 . Switches 413 and 414 are connected in series to the connection point of variable current source 411 and N-type transistor 412 , and these connection points are connected to the gate of N-type transistor 415 . Switches 416 and 417 are connected in series to the connection point of variable current source 411 and N-type transistor 412 , and these connection points are connected to the gate of N-type transistor 418 .

The value of the current supplied by the variable current source 411 is adjusted by a control signal held in a register or the like. Control signals SW10, SW11, SW12 and SW13 for opening and closing switches 413, 414, 416 and 417 are also held in registers or the like.

In the configuration described above, the operator can adjust the value of the gate voltage VGCLP by changing the control signal in the register. Note that the configuration of the gate voltage supply unit 410 is not limited to the circuit illustrated in the figure as long as the gate voltage VGCLP can be changed.

FIG. 32 is a graph showing an example of variations in ground current and streaking amount in the ninth embodiment of the present technology. In the same figure, a is a graph showing an example of variation of the ground current _IGND . b in the figure is a graph showing an example of variation of the difference ΔI _GND between the ground current and the dark current. c in the figure is a graph showing an example of variation in streaking amount. The vertical axis in the figure indicates the current or streaking amount, and the horizontal axis in the figure indicates the voltage VSL of the vertical signal line 229-n. In the same figure, the dotted line indicates variations in ground current and streaking amount in the second embodiment in which the clamp transistor 383 is not provided. On the other hand, the solid line indicates variations in ground current and streaking amount in the ninth embodiment in which the clamp transistor 383 is provided.

As illustrated in the figure, the gate voltage supply unit 410 can adjust the streaking amount by changing the gate voltage VGCLP.

As described above, according to the ninth embodiment of the present technology, the gate voltage supply unit 410 changes the gate voltage VGCLP, so that the streaking amount can be adjusted to a desired value.

<10. Tenth Embodiment>
In the first embodiment described above, the differential amplifier circuit that amplifies the difference between the analog signal Ain and the reference signal REF is used as the comparator 332 in the ADC 331. Power can be further reduced. The solid-state imaging device 200 of the tenth embodiment differs from that of the first embodiment in that power consumption is further reduced.

FIG. 33 is a circuit diagram showing a configuration example of the comparator 420 according to the tenth embodiment of the present technology. In this tenth embodiment, comparator 420 is arranged instead of comparator 331 in each column. Comparator 420 includes capacitors 421, 422 and 430, P-type transistors 423 and 424, switches 425 and 426, and N-type transistors 427-429. As P-type transistor 423, P-type transistor 424, N-type transistor 427, N-type transistor 428 and N-type transistor 429, for example, MOS transistors are used.

One end of each of capacitors 421 and 422 is commonly connected to the gate of N-type transistor 427 . Also, the analog signal Ain is input to the other end of the capacitor 421 through the vertical signal line 229-n. A reference signal REF is input to the other end of the capacitor 422 .

P-type transistors 423 and 424 are connected in parallel to the power supply. The gate of P-type transistor 423 is connected to the drain and the gate of P-type transistor 424 . N-type transistor 427 is inserted between N-type transistor 429 and P-type transistor 423 , and N-type transistor 428 is inserted between N-type transistor 429 and P-type transistor 424 . A predetermined bias voltage Vbc is applied to the gate of the N-type transistor 429 . Also, the potential at the connection point of the P-type transistor 424 and the N-type transistor 428 is supplied to the counter 333 as the comparison result signal of the comparator 420 .

The switch 425 opens and closes between the gate and drain of the N-type transistor 427 . Switch 426 opens and closes between the gate and drain of N-type transistor 428 . Capacitor 430 is inserted between the gate of N-type transistor 428 and the ground terminal.

In the above configuration, capacitors 421 and 422 divide the voltage between analog signal Ain and reference signal REF with a voltage dividing ratio based on their capacitance values. A circuit composed of P-type transistors 423 and 424, switches 425 and 426, and N-type transistors 427 to 429 functions as a differential amplifier circuit. This differential amplifier circuit amplifies the difference between the input voltages from capacitors 421 and 422 and a predetermined voltage from capacitor 430 . The circuit composed of the capacitors 421 and 422 is an example of the dividing circuit described in the claims.

Thus, according to the tenth embodiment of the present technology, the voltage between the analog signal Ain and the reference signal REF is divided and input to the differential amplifier circuit. can be driven at a voltage lower than that of the form of , and power consumption can be reduced.

<11. Example of application to moving objects>
The technology (the present technology) according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure can be realized as a device mounted on any type of moving body such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility, airplanes, drones, ships, and robots. may

FIG. 34 is a block diagram illustrating a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology according to the present disclosure can be applied.

Vehicle control system 12000 comprises a plurality of electronic control units connected via communication network 12001 . In the example shown in FIG. 34, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside information detection unit 12030, an inside information detection unit 12040, and an integrated control unit 12050. Also, as the functional configuration of the integrated control unit 12050, a microcomputer 12051, an audio/image output unit 12052, and an in-vehicle network I/F (interface) 12053 are illustrated.

Drive system control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various programs. For example, the driving system control unit 12010 includes a driving force generator for generating driving force of the vehicle such as an internal combustion engine or a driving motor, a driving force transmission mechanism for transmitting the driving force to the wheels, and a steering angle of the vehicle. It functions as a control device such as a steering mechanism to adjust and a brake device to generate braking force of the vehicle.

Body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a keyless entry system, a smart key system, a power window device, or a control device for various lamps such as headlamps, back lamps, brake lamps, winkers or fog lamps. In this case, body system control unit 12020 can receive radio waves transmitted from a portable device that substitutes for a key or signals from various switches. Body system control unit 12020 receives the input of these radio waves or signals and controls the door lock device, power window device, lamps, etc. of the vehicle.

External information detection unit 12030 detects information external to the vehicle in which vehicle control system 12000 is mounted. For example, the vehicle exterior information detection unit 12030 is connected with an imaging section 12031 . The vehicle exterior information detection unit 12030 causes the imaging unit 12031 to capture an image of the exterior of the vehicle, and receives the captured image. The vehicle exterior information detection unit 12030 may perform object detection processing or distance detection processing such as people, vehicles, obstacles, signs, or characters on the road surface based on the received image.

The imaging unit 12031 is an optical sensor that receives light and outputs an electric signal according to the amount of received light. The imaging unit 12031 can output the electric signal as an image, and can also output it as distance measurement information. Also, the light received by the imaging unit 12031 may be visible light or non-visible light such as infrared rays.

The vehicle interior information detection unit 12040 detects vehicle interior information. The in-vehicle information detection unit 12040 is connected to, for example, a driver state detection section 12041 that detects the state of the driver. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 detects the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041. It may be calculated, or it may be determined whether the driver is dozing off.

The microcomputer 12051 calculates control target values for the driving force generator, the steering mechanism, or the braking device based on the information inside and outside the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, and controls the drive system control unit. A control command can be output to 12010 . For example, the microcomputer 12051 realizes functions of ADAS (Advanced Driver Assistance System) including collision avoidance or shock mitigation of vehicles, follow-up driving based on inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane deviation warning, etc. Cooperative control can be performed for the purpose of

In addition, the microcomputer 12051 controls the driving force generator, the steering mechanism, the braking device, etc. based on the information about the vehicle surroundings acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, so that the driver's Cooperative control can be performed for the purpose of autonomous driving, etc., in which vehicles autonomously travel without depending on operation.

Further, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the information detection unit 12030 outside the vehicle. For example, the microcomputer 12051 controls the headlamps according to the position of the preceding vehicle or the oncoming vehicle detected by the vehicle exterior information detection unit 12030, and performs coordinated control aimed at anti-glare such as switching from high beam to low beam. It can be carried out.

The audio/image output unit 12052 transmits at least one of audio and/or image output signals to an output device capable of visually or audibly notifying the passengers of the vehicle or the outside of the vehicle. In the example of FIG. 34, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are illustrated as output devices. The display unit 12062 may include at least one of an on-board display and a head-up display, for example.

FIG. 35 is a diagram showing an example of the installation position of the imaging unit 12031. As shown in FIG.

In FIG. 35 , imaging units 12101 , 12102 , 12103 , 12104 , and 12105 are provided as imaging unit 12031 .

The imaging units 12101, 12102, 12103, 12104, and 12105 are provided at positions such as the front nose, side mirrors, rear bumper, back door, and windshield of the vehicle 12100, for example. An image pickup unit 12101 provided in the front nose and an image pickup unit 12105 provided above the windshield in the passenger compartment mainly acquire images in front of the vehicle 12100 . Imaging units 12102 and 12103 provided in the side mirrors mainly acquire side images of the vehicle 12100 . An imaging unit 12104 provided in the rear bumper or back door mainly acquires an image behind the vehicle 12100 . The imaging unit 12105 provided above the windshield in the passenger compartment is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, and the like.

Note that FIG. 35 shows an example of the imaging range of the imaging units 12101 to 12104 . The imaging range 12111 indicates the imaging range of the imaging unit 12101 provided in the front nose, the imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided in the side mirrors, respectively, and the imaging range 12114 The imaging range of an imaging unit 12104 provided on the rear bumper or back door is shown. For example, by superimposing the image data captured by the imaging units 12101 to 12104, a bird's-eye view image of the vehicle 12100 viewed from above can be obtained.

At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera composed of a plurality of imaging elements, or may be an imaging element having pixels for phase difference detection.

For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 determines the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and changes in this distance over time (relative velocity with respect to the vehicle 12100). , it is possible to extract, as the preceding vehicle, the closest three-dimensional object on the course of the vehicle 12100, which runs at a predetermined speed (for example, 0 km/h or more) in substantially the same direction as the vehicle 12100. can. Furthermore, the microcomputer 12051 can set the inter-vehicle distance to be secured in advance in front of the preceding vehicle, and perform automatic brake control (including following stop control) and automatic acceleration control (including following start control). In this way, cooperative control can be performed for the purpose of automatic driving in which the vehicle runs autonomously without relying on the operation of the driver.

For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 converts three-dimensional object data related to three-dimensional objects to other three-dimensional objects such as motorcycles, ordinary vehicles, large vehicles, pedestrians, and utility poles. It can be classified and extracted and used for automatic avoidance of obstacles. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into those that are visible to the driver of the vehicle 12100 and those that are difficult to see. Then, the microcomputer 12051 judges the collision risk indicating the degree of danger of collision with each obstacle, and when the collision risk is equal to or higher than the set value and there is a possibility of collision, an audio speaker 12061 and a display unit 12062 are displayed. By outputting an alarm to the driver via the drive system control unit 12010 and performing forced deceleration and avoidance steering via the drive system control unit 12010, driving support for collision avoidance can be performed.

At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not the pedestrian exists in the captured images of the imaging units 12101 to 12104 . Such recognition of a pedestrian is performed by, for example, a procedure for extracting feature points in images captured by the imaging units 12101 to 12104 as infrared cameras, and performing pattern matching processing on a series of feature points indicating the outline of an object to determine whether or not the pedestrian is a pedestrian. This is done by a procedure that determines When the microcomputer 12051 determines that a pedestrian exists in the images captured by the imaging units 12101 to 12104 and recognizes the pedestrian, the audio image output unit 12052 outputs a rectangular outline for emphasis to the recognized pedestrian. is superimposed on the display unit 12062 . Also, the audio/image output unit 12052 may control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.

An example of a vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to, for example, the imaging unit 12031 among the configurations described above. Specifically, the imaging device 100 in FIG. 1 can be applied to the imaging unit 12031 . By applying the technology according to the present disclosure to the imaging unit 12031, it is possible to increase the readout speed and improve the frame rate.

In addition, the above-described embodiment shows an example for embodying the present technology, and the matters in the embodiment and the matters specifying the invention in the scope of claims have corresponding relationships. Similarly, the matters specifying the invention in the scope of claims and the matters in the embodiments of the present technology with the same names have corresponding relationships. However, the present technology is not limited to the embodiments, and can be embodied by various modifications to the embodiments without departing from the scope of the present technology.

In addition, the processing procedure described in the above embodiment may be regarded as a method having a series of procedures, and a program for causing a computer to execute the series of procedures or a recording medium for storing the program You can catch it. As this recording medium, for example, CD (Compact Disc), MD (MiniDisc), DVD (Digital Versatile Disc), memory card, Blu-ray disc (Blu-ray (registered trademark) Disc), etc. can be used.

It should be noted that the effects described in this specification are only examples and are not limited, and other effects may be provided.

Note that the present technology can also have the following configuration.
(1) a logic circuit that processes an analog signal;
a pixel circuit that generates the analog signal by photoelectric conversion and outputs the analog signal to the logic circuit via a predetermined signal line;
and a negative capacitance circuit connected to the predetermined signal line.
(2) the negative capacitance circuit,
an amplifier having an input terminal connected to the predetermined signal line;
The solid-state imaging device according to (1), further comprising a capacitor having both ends connected to the input terminal and the output terminal of the amplifier.
(3) further comprising a current source connected to the predetermined signal line;
The negative capacitance circuit is
an insertion transistor inserted between the current source and the predetermined signal line;
an amplifier consisting of a pair of cascode-connected transistors between a power supply and a reference terminal;
a capacitor having one end connected to a connection point of the pair of transistors and having the other end connected to a connection point between the current source and the insertion transistor;
The solid-state imaging device according to (1), wherein the gate of the transistor connected to the power supply among the pair of transistors is connected to the predetermined signal line.
(4) applying a first bias voltage to the gate of the insertion transistor;
The solid-state imaging device according to (3), wherein the current source includes a second transistor to which a second bias voltage different from the first bias voltage is applied.
(5) applying a first bias voltage to the gate of the insertion transistor;
the current source comprises a second transistor;
The solid-state imaging device according to (3), wherein the gate of the insertion transistor is connected to the gate of the second transistor.
(6) further comprising a current source connected to the predetermined signal line;
The negative capacitance circuit is
an insertion transistor inserted between the current source and the predetermined signal line;
an amplifier having an input terminal connected to the predetermined signal line;
(1), further comprising a capacitor having one end connected to the input terminal of the amplifier and the other end connected to a connection point between the current source and the insertion transistor.
(7) further comprising a current source connected to the predetermined signal line;
The logic circuit is
a comparator that compares the analog signal with a predetermined reference signal and outputs a comparison result;
The solid-state imaging device according to (1), further comprising a control circuit that generates a control signal based on the comparison result and outputs the control signal to the negative capacitance circuit.
(8) the negative capacitance circuit,
an insertion transistor inserted between the current source and the predetermined signal line;
a capacitor;
an amplifier having an input terminal connected to the predetermined signal line;
a first switch that opens and closes a path between one end of the capacitor and an output terminal of the amplifier;
(7), further comprising a second switch for connecting the other end of the capacitor to a connection point between the insertion transistor and the current source or a predetermined reference terminal according to the control signal.
(9) the negative capacitance circuit,
an insertion transistor inserted between the current source and the predetermined signal line;
a capacitor;
an amplifier having an input terminal connected to the predetermined signal line;
a first switch that opens and closes a path between a connection point of the insertion transistor and the current source and one end of the capacitor;
(7), further comprising a second switch for connecting the other end of the capacitor to the output terminal of the amplifier or a predetermined reference terminal in accordance with the control signal.
(10) the comparator,
a dividing circuit that divides the voltage between the analog signal and the predetermined reference signal and outputs it as an input voltage;
The solid-state imaging device according to any one of (7) to (9), further comprising a differential amplifier circuit that amplifies a difference between the input voltage and a predetermined voltage.
(11) further comprising a current source connected to the predetermined signal line;
The negative capacitance circuit is
an insertion transistor inserted between the current source and the predetermined signal line;
an amplifier having an input terminal connected to the predetermined signal line;
and a switched capacitor circuit,
The switched capacitor circuit is
a capacitor;
a first input side switch that opens and closes a path between the output terminal of the amplifier and one end of the capacitor;
a second input switch that opens and closes a path between the connection point of the insertion transistor and the current source and the other end of the capacitor;
a first output side switch that opens and closes a path between the one end and the logic circuit;
The solid-state imaging device according to (1), further comprising a second output side switch for opening and closing a path between the other end and a predetermined reference terminal.
(12) The pixel circuit is arranged on a first semiconductor chip,
The solid-state imaging device according to any one of (1) to (11), wherein the negative capacitance circuit and the logic circuit are arranged on a second semiconductor chip stacked on the first semiconductor chip.
(13) further comprising a first current source connected to the predetermined signal line;
The negative capacitance circuit is
an insertion transistor inserted between the first current source and the predetermined signal line;
a second current source;
an N-type transistor inserted between the second current source and a power supply and having a gate connected to the predetermined signal line;
a clamp transistor connected in parallel with the N-type transistor between the power supply and the second current source;
Any one of (1) to (12) above, comprising a capacitor having both ends connected to a connection point between the insertion transistor and the first current source and a connection point between the N-type transistor and the second current source. solid-state image sensor.
(14) The solid-state imaging device according to (13), further comprising a gate voltage supply section that changes the gate voltage of the clamp transistor.
(15) a logic circuit that processes an analog signal and outputs a digital signal;
a pixel circuit that generates the analog signal by photoelectric conversion and outputs the analog signal to the logic circuit via a predetermined signal line;
a negative capacitance circuit connected to the predetermined signal line;
and a recording unit that records the digital signal.

100 imaging device 110 imaging lens 120 recording unit 130 imaging control unit 200 solid-state imaging device 201 pixel chip 202 logic chip 210 vertical driver 220 pixel array unit 230 pixel circuit 231 photodiode 232 transfer transistor 233 reset transistor 234 floating diffusion layer 235 amplification transistor 236 Selection transistor 240 Timing control unit 250, 371 DAC
260 horizontal transfer scanning circuit 270 image signal processing unit 300 column signal processing unit 301 upper column signal processing unit 302 lower column signal processing unit 310 negative capacitance circuit 311, 314, 351 amplifier 312, 342, 356, 357, 372, 421 , 422, 430 Capacitors 313, 315, 316, 321, 321-1, 321-2, 412, 415, 418, 427, 428, 429 N-type transistors 320, 381, 382 Current sources 331, 370 ADC
332, 374, 420 comparator 333 counter 334, 341, 343, 352 to 355, 358 to 361, 373, 413, 414, 416, 417, 425, 426 switch 335 memory 350 sample hold circuit 375 successive approximation controller 383 clamp Transistor 410 Gate voltage supply unit 411 Variable current source 423, 424 P-type transistor 12031 Imaging unit

Claims (13)

logic circuitry for processing analog signals;
a pixel circuit that generates the analog signal by photoelectric conversion and outputs the analog signal to the logic circuit via a predetermined signal line;
a negative capacitance circuit connected to the predetermined signal line ;
a current source connected to the predetermined signal line;
and
The negative capacitance circuit is
an insertion transistor inserted between the current source and the predetermined signal line;
an amplifier having an input terminal connected to the predetermined signal line;
a capacitor having one end connected to the output terminal of the amplifier and the other end connected to a connection point between the current source and the insertion transistor;
have
Solid-state image sensor. The negative capacitance circuit is
the insertion transistor;
said amplifier comprising a pair of cascode-connected transistors between a power supply and a reference terminal;
a capacitor having one end connected to a connection point of the pair of transistors and having the other end connected to a connection point between the current source and the insertion transistor;
2. A solid-state imaging device according to claim 1, wherein the gate of the transistor connected to the power supply among the pair of transistors is connected to the predetermined signal line. a first bias voltage is applied to the gate of the insertion transistor;
3. A solid-state imaging device according to claim 2 , wherein said current source comprises a second transistor to which a second bias voltage different from said first bias voltage is applied. a first bias voltage is applied to the gate of the insertion transistor;
the current source comprises a second transistor;
3. A solid-state imaging device according to claim 2 , wherein the gate of said insertion transistor is connected to the gate of said second transistor. further comprising a current source connected to the predetermined signal line;
The logic circuit is
a comparator that compares the analog signal with a predetermined reference signal and outputs a comparison result;
2. The solid-state imaging device according to claim 1, further comprising a control circuit for generating a control signal based on said comparison result and outputting it to said negative capacitance circuit. The negative capacitance circuit is
the insertion transistor;
the capacitor;
the amplifier ;
a first switch that opens and closes a path between one end of the capacitor and an output terminal of the amplifier;
6. A solid-state imaging device according to claim 5 , further comprising a second switch for connecting the other end of said capacitor to a connection point between said insertion transistor and said current source or a predetermined reference terminal according to said control signal. The negative capacitance circuit is
the insertion transistor;
the capacitor;
the amplifier ;
a first switch that opens and closes a path between a connection point of the insertion transistor and the current source and one end of the capacitor;
6. A solid-state imaging device according to claim 5 , further comprising a second switch for connecting the other end of said capacitor to an output terminal of said amplifier or a predetermined reference terminal according to said control signal. The comparator is
a dividing circuit that divides the voltage between the analog signal and the predetermined reference signal and outputs it as an input voltage;
6. A solid-state imaging device according to claim 5 , further comprising a differential amplifier circuit for amplifying a difference between said input voltage and a predetermined voltage. The negative capacitance circuit is
the insertion transistor;
the amplifier ;
and a switched capacitor circuit,
The switched capacitor circuit is
the capacitor;
a first input side switch that opens and closes a path between the output terminal of the amplifier and one end of the capacitor;
a second input switch that opens and closes a path between the connection point of the insertion transistor and the current source and the other end of the capacitor;
a first output side switch that opens and closes a path between the one end and the logic circuit;
2. A solid-state imaging device according to claim 1, further comprising a second output side switch for opening and closing a path between said other end and a predetermined reference terminal. The pixel circuit is arranged on a first semiconductor chip,
2. A solid-state imaging device according to claim 1, wherein said negative capacitance circuit and said logic circuit are arranged on a second semiconductor chip laminated on said first semiconductor chip. the current source comprises a first current source;
The negative capacitance circuit is
the insertion transistor;
said amplifier and
with
The amplifier
a second current source;
an N-type transistor inserted between the second current source and a power supply and having a gate connected to the predetermined signal line;
a clamp transistor connected in parallel with the N-type transistor between the power supply and the second current source;
2. A solid-state imaging device according to claim 1, further comprising said capacitor having both ends connected to a connection point between said insertion transistor and said first current source and a connection point between said N-type transistor and said second current source. 12. The solid-state imaging device according to claim 11 , further comprising a gate voltage supply unit that changes the gate voltage of said clamp transistor. a logic circuit that processes an analog signal and outputs a digital signal;
a pixel circuit that generates the analog signal by photoelectric conversion and outputs the analog signal to the logic circuit via a predetermined signal line;
a negative capacitance circuit connected to the predetermined signal line;
a recording unit that records the digital signal ;
a current source connected to the predetermined signal line;
and
The negative capacitance circuit is
an insertion transistor inserted between the current source and the predetermined signal line;
an amplifier having an input terminal connected to the predetermined signal line;
a capacitor having one end connected to the output terminal of the amplifier and the other end connected to a connection point between the current source and the insertion transistor;
have
Imaging device.

Images